Building a C43 Engine - Normal Asperation

[speedybenz]

I build a lot of AMA Supersport engines over the course of a year and have been looking at my C43 engine and trying not to pul it out of the car. But I keep hearing a voice voice in my head telling me to build it, build it.

So here are some of my thoughts on this:

1. Would like to increase rpm limit to 7500rpm. Even at that engine speed the stress will be less than a M3 engine which spins to 8000rpm with a longer stroke. So this is very doable with better rods and pistons. Need a chip tuner who can increase the rpm limit to 7500rpm.

2. Need good hand built headers, $1000

3. Need to examine the valve train weights and cam profiles to ensure that the valves can follow the cam at the increased engine speeds. Should not be an issue, ie; Webcam, Comp cams, etc.

4. I am almost positve the intake and exhuast ports are too large to function properly, so weld up exhaust ports and JB weld intake ports. Perform a very good 3-angle valve job.

5. Reduce intake & exhaust valve weight. Current Japanese engines are using 5mm valve stems with valve heade diameters as large or larger than whats in the C43, so have new valve guides machined to use lighter valves.

6. JE and Wiesco both make some good pistons, so find one with the proper diameter and weight.

7. Carrilllo will make a set of custom connecting rods to any length and bearing size. Carillo rods do not break.

8. Have the crank inspected and have the rod journals offset ground to use Honda sized bearing in the new Carillo rods. This results in lower bearing speed and thus less friction, more Hp.

9. Auto tranny and Torque convertor inspected to handle increase rpm and hp.

10. Rear diff. need to go to a 3.46:1 gear ratio to take advantage of the increased rpm


So with all the above you could possibliy have a well built engine that could be very reliable and spin to 7500rpm.

If you can achieve a 1.2 foot-pounds of torque per cubic inch of motor, which is around what a S2000 makes, then you could end up with about 320 ft-lbs of Tq and approx. 450Hp.

Very fun project.

Any thoughts and comments?

Jeff

[714guy]

go for it Jeff, and document it along the way so i can learn some stuff. If anybody can do this its you.

good luck

[J.HIDALGO]

if you are willing to take the challenge. Nowadays, with Kleemann, Brabus and even with MB going to Kompressors instead of normal aspirated engines to increase HP. Would it be cheaper to go "normal" aspirated vs kompressor?
Plus, I am not sure if with the kompressors you need extra work with the transmission, intake, exhaust, differentials and (you did not mention) brakes.
Maybe some of the gurus here can give us the inside...

[speedybenz]

With extra rpm I will want to make sure the valves both intake and exhaust will follow the cam shaft.

As for the transmission I would think 7000 to 7500 rpm will be fine, maybe I will go to a higher stall speed torque convertor.

As for brakes I have updated my C43 brakes will a full bore race spec system from The Brake Man.

As for cost, since I can do most of the labor myself that will reduce the expense quite a bit.

Jeff

[pentoman]

Will you lighten the flywheel? What effect do you think that would have, particularly with an automatic?